Fix migrating multiple DBs with pending migration action

This was supposed to work with multiple DBs, but the task code and the
migration code have fallen out of sync and the pending migration action
only works against primary. With this patch, we use
`ActiveRecord::Tasks::DatabaseTasks.migrate_all` for both, and introduce
`ActiveRecord::Tasks::DatabaseTasks.dump_all` to use in the task and
action.

Author: gmcgibbon

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Fix migrating multiple databases with `ActiveRecord::PendingMigration` action.
+
+    *Gannon McGibbon*
+
 *   Enable automatically retrying idempotent association queries on connection
     errors.
 

activerecord/lib/active_record/migration.rb

@@ -148,11 +148,10 @@ class PendingMigrationError < MigrationError # :nodoc:
     include ActiveSupport::ActionableError
 
     action "Run pending migrations" do
-      ActiveRecord::Tasks::DatabaseTasks.migrate
+      ActiveRecord::Tasks::DatabaseTasks.migrate_all
 
       if ActiveRecord.dump_schema_after_migration
-        connection = ActiveRecord::Tasks::DatabaseTasks.migration_connection
-        ActiveRecord::Tasks::DatabaseTasks.dump_schema(connection.pool.db_config)
+        ActiveRecord::Tasks::DatabaseTasks.dump_all
       end
     end
 

activerecord/lib/active_record/railties/databases.rake

@@ -447,11 +447,7 @@ db_namespace = namespace :db do
   namespace :schema do
     desc "Create a database schema file (either db/schema.rb or db/structure.sql, depending on `ENV['SCHEMA_FORMAT']` or `config.active_record.schema_format`)"
     task dump: :load_config do
-      ActiveRecord::Tasks::DatabaseTasks.with_temporary_pool_for_each do |pool|
-        db_config = pool.db_config
-        schema_format = ENV.fetch("SCHEMA_FORMAT", ActiveRecord.schema_format).to_sym
-        ActiveRecord::Tasks::DatabaseTasks.dump_schema(db_config, schema_format)
-      end
+      ActiveRecord::Tasks::DatabaseTasks.dump_all
 
       db_namespace["schema:dump"].reenable
     end

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -428,6 +428,14 @@ def reconstruct_from_schema(db_config, format = ActiveRecord.schema_format, file
         end
       end
 
+      def dump_all
+        with_temporary_pool_for_each do |pool|
+          db_config = pool.db_config
+          schema_format = ENV.fetch("SCHEMA_FORMAT", ActiveRecord.schema_format).to_sym
+          ActiveRecord::Tasks::DatabaseTasks.dump_schema(db_config, schema_format)
+        end
+      end
+
       def dump_schema(db_config, format = ActiveRecord.schema_format) # :nodoc:
         return unless db_config.schema_dump
 

railties/test/application/configuration_test.rb

@@ -159,7 +159,7 @@ class MyLogger < ::Logger
       assert_match(/You're using a cache/, error.message)
     end
 
-    test "a renders exception on pending migration" do
+    test "renders an exception on pending migration" do
       add_to_config <<-RUBY
         config.active_record.migration_error    = :page_load
         config.consider_all_requests_local      = true
@@ -200,6 +200,67 @@ def change
       end
     end
 
+    test "renders an exception on pending migration for multiple DBs" do
+      add_to_config <<-RUBY
+        config.active_record.migration_error    = :page_load
+        config.consider_all_requests_local      = true
+        config.action_dispatch.show_exceptions  = :all
+      RUBY
+
+      app_file "config/database.yml", <<-YAML
+        <%= Rails.env %>:
+          primary:
+            adapter: sqlite3
+            database: 'dev_db'
+          other:
+            adapter: sqlite3
+            database: 'other_dev_db'
+            migrations_paths: db/other_migrate
+      YAML
+
+      app_file "db/migrate/20140708012246_create_users.rb", <<-RUBY
+        class CreateUsers < ActiveRecord::Migration::Current
+          def change
+            create_table :users
+          end
+        end
+      RUBY
+
+      app_file "db/other_migrate/20140708012247_create_blogs.rb", <<-RUBY
+        class CreateBlogs < ActiveRecord::Migration::Current
+          def change
+            create_table :blogs
+          end
+        end
+      RUBY
+
+      app "development"
+
+      begin
+        ActiveRecord::Migrator.migrations_paths = ["#{app_path}/db/migrate", "#{app_path}/db/other_migrate"]
+
+        get "/foo"
+        assert_equal 500, last_response.status
+        assert_match "ActiveRecord::PendingMigrationError", last_response.body
+
+        assert_changes -> { File.exist?(File.join(app_path, "db", "schema.rb")) }, from: false, to: true do
+          output = capture(:stdout) do
+            post "/rails/actions", { error: "ActiveRecord::PendingMigrationError", action: "Run pending migrations", location: "/foo" }
+          end
+
+          assert_match(/\d{14}\s+CreateUsers/, output)
+          assert_match(/\d{14}\s+CreateBlogs/, output)
+        end
+
+        assert_equal 302, last_response.status
+
+        get "/foo"
+        assert_equal 404, last_response.status
+      ensure
+        ActiveRecord::Migrator.migrations_paths = nil
+      end
+    end
+
     test "Rails.groups returns available groups" do
       require "rails"